The present invention relates to interoperability among various wireless devices for vehicular communications, and, more particularly, to enabling interoperability of dual-radio and single-radio devices for vehicular multi-channel operations.
Referring now to FIG. 1, the problem of interoperability among various wireless devices for vehicular communications is illustrated. There are two types of devices in close vicinity:
1) Legacy single-radio devices 102 that operate on the control channel (channel 176 in the US) for support both safety application and control of service applications and a service channel for support data delivery of service applications through periodic channel switching, and
2) Advanced dual-radio devices 104 that tune one of their radios always on the safety channel (channel 172 in the US) and use the other radio switching channels between the control channel (channel 176) and a service channel to support non-safety service applications.
Note that the Control Channel (CCH) Interval of the advanced dual-radio devices would be smaller (or much smaller) than that of the legacy single radio devices, since all safety message communications should use the dedicated Safety Channel and only the control message communications for support service application should be on the CCH, as opposed to the legacy single radio devices that have to provide supports for safety applications and control of service application on the CCH. A smaller CCH interval of the advanced dual-radio devices allows a larger SCH interval that can more effectively support data delivery of service applications.
A dedicated radio of the advanced dual-radio device that is always on the Safety channel allows the safety-critical communications to be conducted on a much less congested RF channel such that the packet delivery performance can be significantly improved.
When the legacy single radio devices and the advanced dual-radio devices are communicating in close proximity, safety-critical messages communications can not be effectively conducted among these different types of devices due to the fact that the specifications of channel operation of these devices are not fully interoperable.
Due to the longer length of the CCH interval of the single-radio device compared to the one of the dual-radio devices, the safety message transmitted by the legacy single-radio devices on the CCH may not be received by the dual-radio devices in a timely manner.
Since the advance dual-radio devices transmit the safety messages on the Safety channel that the legacy single-radio devices do not tune to, those safety messages on the safety channel will not be received by the legacy single-radio devices.
What is desired is a method for enabling interoperability among the legacy and advanced wireless vehicular devices for ensuring communication reliability of safety-critical applications, while maintaining the desirable advantages of these devices (i.e. low-cost, simple operations for the legacy devices, and higher performance and spectrum efficient for the advanced devices).